Processor Fundamentals

Worked examples (6)

• 1Identify the roles of the MAR, MDR and PC
• 2Classify the three system buses
• 3Trace the fetch stage with register transfer notation
• 4Explain two factors that affect CPU performance
• 5How an interrupt is detected and serviced
• 6Why more cores can beat a faster single core

Model answers (6)

• ✓Model answer — 9618 Paper 1 style
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• ✓Model answer — 9618 Paper 1 style

Worked examples (6)

• 1Load a value and store it elsewhere
• 2Immediate addressing with ADD #n
• 3Trace a counting loop with a trace table
• 4Indexed addressing to read a list
• 5Indirect addressing with LDI
• 6Full program trace — sum a list with an indexed loop

Model answers (6)

• ✓Model answer — 9618 Paper 1 style
• ✓Model answer — 9618 Paper 1 style
• ✓Model answer — 9618 Paper 1 style
• ✓Model answer — 9618 Paper 1 style
• ✓Model answer — 9618 Paper 1 style
• ✓Model answer — 9618 Paper 1 style

Worked examples (6)

• 1Logical shift left by 2 (LSL #2)
• 2Logical shift right by 1 (LSR #1)
• 3Test a single bit with a mask (AND)
• 4Set a single bit with a mask (OR)
• 5Toggle a bit with XOR
• 6Monitor and control a device with bit masking

Model answers (6)

• ✓Model answer — 9618 Paper 1 style
• ✓Model answer — 9618 Paper 1 style
• ✓Model answer — 9618 Paper 1 style
• ✓Model answer — 9618 Paper 1 style
• ✓Model answer — 9618 Paper 1 style
• ✓Model answer — 9618 Paper 1 style